Description: It is a slender shrubby cactus that has a similar form and habitat to the night-blooming cereus (Peniocereus greggii). It puts forth many basal shoots, soon becoming tillered.Stems: Branched, bluish mottled in purple and green, erect or semi prostrate , up to 1.8 m long or more, 2 cm inches in diameter;Roots: Tuberose and succulent, Even adventitious roots of Monvillea spegazzinii become succulent.Ribs: Three to five (usually four) raised angular that have deep incisions similar to indentations along the edge. They are about 3 cm long at the base and bear small areoles at the apex of the protuberances.Central spines: One (or any) up to1.5 cm long;Radial spines: The Young plants usually have three sharp, blackish spines 5 mm long, two pointing upward and one downward. On the older parts there are five radial and one central spine, 1.5 cm. long.Flowers: 10 to 13 cm in length with a slender tube, reddish outer perianth segments and white inner ones. They arise from near the top on the sides of the stems; buds point upward but curve suddenly downward when the flowers open. They bloom at night.Fruit: Smooth, red, juicy with persistent perianth remnant that withers slowly and dries attached to the end of the fruit. Flowers.Remarks: These plants frequently produce monstrose crests, and crests occasionally produce normal shoots. The crested variety have spectacular blue marbled stems with pronounced sculpture effects

Cultivation and Propagation: Paraguay and northeastern Argentina. It was discovered near Resistencia, capital of the province of Chaco, Argentina.Habitat: It has little capacity to swell or shrink during rainy/dry cycles. It occurs in only moderately dry areas, growing among leafy shrubs and small trees.